The emergence of variants of concern in late 2020 hearkened a shift in the COVID-19 pandemic as “variants” entered the public lexicon. The acceleration of the Delta variant around the world is raising questions about its origin, transmissibility, hotspots and potential for vaccine resistance.

What is a variant?

Through genome sequencing, we can determine specific orders of individual genes and the nucleotides that make up strands of DNA and RNA. If we think of the virus as a book, it’s as though all of the pages have been cut up into pieces. Sequencing allows us to determine all of the words and sentences in their proper order. Variants differ from one another based on mutations. So, two copies of the book would be “variants” if one or more of the cut-up pieces were different.

We should also appreciate that variants have been emerging throughout the pandemic with no effect on viral behaviours. However, the emergence of variants of concern, where mutations have resulted in altered virus characteristics (increased transmission and disease severity, reduced vaccine effectiveness, detection failure) have had deleterious health consequences.

Emergence and transmission of B.1.1.7 (Alpha), B.1.351 (Beta) and P.1 (Gamma) in Canada resulted in third waves of transmission leading to overwhelmed health-care systems and implementation of further restrictions. The World Health Organization introduced a new naming system, based on the Greek alphabet, for coronavirus variants in the spring 2021.